Treatment of Yarn Dyeing Wastewater Using Different Coagulants Followed by Activated Carbon Adsorption

Abstract

Yarn dyeing industry consumes large volumes of water and chemicals for wet processing of yarn. The chemical reagents used are very diverse in chemical composition, ranging from inorganic and organic compounds to polymers. The major environmental problem of colorant manufacturing is the removal of dyes from effluents. In this study, the potential of using different coagulants such as alum, ferric chloride, and magnesium chloride were investigated for the treatment of dying wastewater. Alum, magnesium chloride and ferric chloride were tested. Lime, cationic and anionic polymers were used as a coagulant aid. To achieve better performance post treatment using granule activated carbon (GAC) was applied as an adsorbent. The use of 500 mg/l alum aided with 400 mg/l lime and 0.35 mg/l cationic polymer achieved the highest removal rate followed by magnesium chloride then ferric chloride. The removal rates of COD, TSS, and turbidity were 69.5 %, 70.7 %and 96.9 %, Post treatment using GAC enhanced the color and COD removals. Their removal rates reached 94.6% and 77.5%, respectively.